The Golgi stains on the new-born guinea pigs will be continued, and the branching of both olivo-cochlear and cochlear nerve fibers studied by both light and electron microscopy. Dye-injection methods will also be employed. Recent observations by scanning electron microscopy on the peripheral vestibular system have revealed new details about hair cell structure. These will be studied further in order to clarify the pattern. The cupula and otolithic membranes lend themselves readily to scanning electron microscopy. New techniques and different preparation methods will be utilized to preserve the structure of the extra-cellular gelatinous membranes. The ears of several small birds have already been embedded for study by light and electron microscopic methods. Their basilar papillae will be studied to determine the distribution of different types of hair cells and the kinociliar orientation.